New Mission Support

Request for ILRS laser ranging tracking support of new missions must be formally submitted to the ILRS Central Bureau (CB), reviewed by the Missions Standing Committee (MSC) and approved by the ILRS Governing Board (GB).

The ILRS was established to support applications and programs in geodesy, geodynamics, and space science; the service's primary emphasis is placed on tasks that support the IAG's Global Geodetic Observing System (GGOS). As of 2018, the ILRS network ranges to more than 100 satellites and missions continue to submit additional requests for tracking support. The ILRS reviews new Mission Support Requests (MSRs) on the basis of laser tracking need and the likelihood of mission success. Although the ILRS tries to accommodate all new tracking requests, the submission of a request does not guarantee ILRS support.

New missions requesting ILRS tracking support should review the following Guidelines for Submitting an ILRS New Mission Support Request to ensure the ILRS can support the upcoming mission. Following this review, the mission must then complete an ILRS SLR Mission Support Request Form. The ILRS will consider the following points when reviewing the submitted MSR form:

  • Does SLR provide a unique capability that other tracking systems cannot? Is SLR the primary or secondary tracking technique? Can the tracking requirement be met by another technique?
  • What added value will SLR data provide to the data products?
  • Has the mission sufficiently quantified its tracking requirement (accuracy, data volume, coverage, etc.)? A request for "Everything you can get" and "do the best you can do" would result in a very low priority for the ILRS.
  • Does the mission have a vulnerable payload aboard that will require special tracking procedures?
  • What is the procurement source of the retroreflector array(s)? Does the design include accommodation for the velocity aberration? See https://ilrs.cddis.eosdis.nasa.gov/technology/spaceSegment/ for more information.
  • Has the signal link budget been estimated either through comparison with spacecraft already tracked by SLR or through the link equation?
  • Have provisions been made to provide reliable predictions in CPF format? Has this source tested their CPF files or are there plans to do such testing? See https://ilrs.cddis.eosdis.nasa.gov/data_and_products/predictions/index.html and https://ilrs.cddis.eosdis.nasa.gov/data_and_products/formats/cpf.html for more information.

The ILRS expects missions to submit their official MSR form at least 6 months prior to launch or from when missions expect tracking support to begin. Upon completion and submission to the CB, the forms are forwarded to the MSC for review, iteration with the user, if necessary, and development of a recommendation on ILRS support including tracking priorities. This recommendation takes into consideration the realism of the program, anticipated scientific achievements and interest of others in these results, the ILRS role in the mission, and the overall tracking load on the ILRS network. After MSC review, the CB then submits the request to the Governing Board for approval.

Once tracking support is approved, the ILRS Central Bureau works with the new missions to establish the level of tracking, the schedule, the points of contact, and the channels of communication. To avoid confusion at the field stations, all communications from the missions to the tracking stations must go through the CB unless otherwise authorized by the CB. New missions normally receive very high priority during the acquisition and checkout phases after launch and are then placed at a routine priority based on the satellite category and orbital parameters.

It is important that missions supported by the ILRS acknowledge the service in papers and presentations that rely on SLR and results. Papers can reference the following citation:

Pearlman, M.R., Degnan, J.J., and Bosworth, J.M., "The International Laser Ranging Service", Advances in Space Research, Vol. 30, No. 2, pp. 135-143, July 2002, DOI:10.1016/S0273-1177(02)00277-6.

The SLR community relies on these acknowledgements and references to strengthen its requests for continued support from its funding organizations.

Prior to launch, the mission requestor should:

  • Complete and submit an ILRS SLR Mission Support Request Form (MSR) to the ILRS Central Bureau (CB) 6 months prior to when anticipated support is required, highlighting any extraordinary conditions or support that will be required.
  • Keep the ILRS CB informed of anticipated mission launch schedules.
  • Three months prior to launch, contact the ILRS CB to schedule tests of prediction (in Consolidated Prediction Format, CPF) and data transfer procedures.
    • Sample CPF should be submitted to the ILRS CB for review to ensure data format
    • Test flow of CPF files to CDDIS and EDC Data Centers using ftp
  • One month prior to launch, mission contacts will review previously submited MSR and provide any updates to the ILRS CB.

Post launch, the mission requestor should:

  • As soon as possible following launch, inform the CB of key tracking parameters (e.g., NORAD number and COSPAR ID). A sample CPF should be submitted for review to ensure usability by the ILRS stations. The mission should specify the timeframe for ILRS tracking to commence.
  • Report at ILRS meetings on mission results and the contributions of SLR to these results.
  • Keep the ILRS community (stations, CB) informed of changes to the mission status (e.g., maneuvers, system problems, etc.) that could affect SLR tracking.

Prior to launch, the ILRS CB will:

  • Provide the mission with all procedures to follow for the Mission Support Request form, prediction generation and delivery, etc.
  • Provide the mission with satellite SIC number.
  • Three months prior to launch, coordinate all CPF testing including data flow. Ensure data format.
  • One month prior to launch, send a message of reminder to mission to review Mission Support Request form.
  • Just prior to launch, coordinate a notice of upcoming mission support to the ILRS stations.

Post launch, the ILRS CB will:

  • Inform the ILRS operations and data centers of the new mission, providing all necessary information (e.g., COSPAR ID, SIC number, normal point interval, prediction provider, special support instructions, start date) to begin data transfer and archive.
  • Issue a notice to the ILRS stations and general community announcing the new mission and providing all necessary information to commence tracking.
  • Issue new mission reports weekly detailing tracking statistics through SLReport with copies to mission contacts.
  • Monitor tracking progress to ensure adequate support is provided.

Additional Information